The invention relates to a microsystem provided in a flat substrate and comprising:                at least two oscillating masses connected to the substrate by flexible suspension means,        excitation means for exciting said oscillating masses in a predetermined excitation direction,        and detection means for detecting movement of said oscillating masses in a measuring direction perpendicular to said excitation direction,said detection means comprising an excitation frame associated with each oscillating mass, and a mobile detection element surrounded by the corresponding excitation frame and comprising a plurality of mobile electrodes, and first and second sets of interconnected fixed electrodes fixedly secured to the substrate on which they are formed, each mobile electrode being arranged between associated fixed electrodes of the first and second sets to form two variable differential capacitors.        